Draco Malfoy is a Werewolf

There are a lot of Harry Potter theories that have existed in the series' fandom, such as Snape being a vampire or Sirius and Remus being secret lovers. Many of these theories have been contradicted by the books themselves, and others seem to have little evidence supporting them in canon.

One such theory, however, bears notice. Draco Malfoy is an annoying antagonist throughout all seven Harry Potter books, but noticeably less so in the sixth and seventh. Presumably, he stops his sophomoric pranks as a consequence of his highly stressful year-long assignment to play a key role in the assassination of Albus Dumbledore.

However, there may be an even more powerful reason for the trajectory of Draco's character development in these latter books. This is that between the fifth and sixth books, directly after Lucius Malfoy has failed to retrieve the prophecy, Voldemort allows Fenrir Greyback to bite his son, Draco.

We've gone back through the 6th and 7th books, and compiled some of the most convincing evidence below:

Draco is not a Death Eater

At the beginning of the 6th book when Harry is hiding in Borgin and Burkes, Draco threatens Borgin, and shows him something on his arm. Harry thinks the thing on Draco's arm is a Dark Mark, but we never see this.

Harry always immediately assumes things and they turn out to be false. If Harry wakes up in the middle of the night months later it is usually right, or if he talks about it with Hermione and Hermione gets it, then it's right. Hermione doesn't think Draco is a Death Eater, so he probably isn't.

Another reason Draco probably doesn't have a Dark Mark is that at the end of the sixth book there is a barrier to the Astronomy Tower that you can only pass through if you have a Dark Mark. This barrier goes up immediately after Draco goes up to the tower, and comes down just before he goes down.

Additionally, Draco is never treated as a Death Eater (and there is no reason for Voldemort to give Draco a Dark Mark).

So what is he?

One ongoing arc in the 6th book is that Draco is sickly and stressed out. This is supposedly because of his quest, but Rowling does this misdirection a lot.

Fenrir Greyback is introduced as a character who specifically punishes people who've messed up by biting their children. Remus Lupin is explicitly mentioned as an example of this. Why set this up if not to use it later?

Relatedly, Lucius's demonstrated punishments do not seem severe enough for his transgressions at the end of the 5th book, by the standards we are supposed to expect from Voldemort by this point in the series. It is also important to keep in mind that Lucius also mishandled Riddle's Diary, resulting in the destruction of one seventh of Voldemort's soul. It is likely that Lucius's additional punishment was unspeakably terrible.

Voldemort says, "Maybe you can babysit the cubs," to Draco when the Death Eaters find out that Remus and Tonks are having a baby. This is a throwaway if he is not a werewolf.

For us, the nail in the coffin is that, while showing Borgin the mark on his arm, Draco says that Fenrir Greyback is a close personal friend and he'd hate for him to have a to pay a visit.

And if the thing on Draco's arm in Borgin & Burkes' was not a Dark Mark (which it's not), what else could he have possibly shown Borgin to make him so frightened?

Finally, Rowling has said in an interview that one scene in the third movie, there was a moment that foreshadowed something she knew was coming that gave her chills. In that movie, Draco impersonates a werewolf and does a wolf howl.

This also works for the arc for the flipping of the Malfoy family, who take care of themselves instead of following Voldemort. It makes more sense for them to throw away decades of servitude if one of them has been turned into a half-blood, making them idealogically incompatible with Voldemort's pure-blood regime.

So why hide it?

There is precedent for J.K. Rowling revealing only the tip of the iceberg in some of her characterizations. For example, Rowling was originally going to write a whole arc about Dean Thomas's family, but instead she focused on Neville. Additionally, Dumbledore's love of Grindelwald is never addressed during any of the books, and was only revealed by J.K. Rowling during a Q&A after all the books had been published. There are likely many other elements of the story that have been left behind the scenes for one reason or another. It may be entirely possible that Draco's reveal was planned for the seventh book, for example, but got cut for pages.

Rowling has new content being released by book, and could be saving this to reveal on Pottermore for the seventh book.

One reason this would be really cool:

It makes Draco's relationship with Snape even more interesting if Draco is relying on him for Wolfsbane potion.

Disclaimer

We have no ownership of Harry Potter or any related content, but we do feel pretty strongly about this theory. Hopefully it will be borne out in time!